fix($compile): workaround for IE11 MutationObserver

IE11 MutationObserver breaks consecutive text nodes into several text nodes.
This patch merges consecutive text nodes into a single node before
looking for interpolations.

Closes #11781

Author: lgalfaso

src/ng/compile.js

@@ -1545,6 +1545,13 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           }
           break;
         case NODE_TYPE_TEXT: /* Text Node */
+          if (msie === 11) {
+            // Workaround for #11781
+            while (node.parentNode && node.nextSibling && node.nextSibling.nodeType === NODE_TYPE_TEXT) {
+              node.nodeValue = node.nodeValue + node.nextSibling.nodeValue;
+              node.parentNode.removeChild(node.nextSibling);
+            }
+          }
           addTextInterpolateDirective(directives, node.nodeValue);
           break;
         case NODE_TYPE_COMMENT: /* Comment */

test/ng/compileSpec.js

@@ -2992,6 +2992,25 @@ describe('$compile', function() {
     }));
 
 
+    it('should handle consecutive text elements as a single text element', inject(function($rootScope, $compile) {
+      // No point it running the test, if there is no MutationObserver
+      if (!window.MutationObserver) return;
+
+      // Create and register the MutationObserver
+      var observer = new window.MutationObserver(noop);
+      observer.observe(document.body, {childList: true, sublist: true});
+
+      // Run the actual test
+      var base = jqLite('<div>&mdash; {{ "This doesn\'t." }}</div>');
+      element = $compile(base)($rootScope);
+      $rootScope.$digest();
+      expect(element.text()).toBe("— This doesn't.");
+
+      // Unregister the MutationObserver (and hope it doesn't mess up with subsequent tests)
+      observer.disconnect();
+    }));
+
+
     it('should support custom start/end interpolation symbols in template and directive template',
         function() {
       module(function($interpolateProvider, $compileProvider) {